PITTSBURGH – A demotion to the minors is usually met with resentment and disappointment from a major-leaguer. When Kirk Nieuwenhuis was sent down to Triple-A Las Vegas, he reacted differently.

Nieuwenhuis was honest with himself. He had been sidelined for the majority of spring training with a knee injury. He didn’t get many at-bats when the season started because playing time was spare as the Mets’ fifth outfielder.

“Honestly, I was happy to get the at-bats in Triple-A,” Nieuwenhuis said. “I knew I needed it. Not getting all those spring training at-bats really caught up to me. I just couldn’t get anything going. There’s no question it was good for me. I was thankful for the at-bats down there.”

Nieuwenhuis’s inclusion on the 25-man roster out of spring training was a surprise considering his limited playing time in Florida. And he didn’t play well. Pegged as a defensive replacement late in games, he recorded just two hits and a walk in 17 plate appearances.

The 25-year-old was optioned April 23 and initially scuffled out west. But he rebounded to post the power numbers the Mets brass expect from the 2008 third-round draft pick.

The outfielder socked eight of his 10 home runs over his final 16 games in the minors. He had compiled a .486 slugging percentage when the Mets designated Rick Ankiel for assignment and called Nieuwenhuis back up June 8.

Since his return, he has platooned with Juan Lagares in center field, playing when a right-handed starting pitcher opposes the Mets. He has started 15 games and been part of the Mets outfield's recent resurgence.

He hit the game-winning home run against the Cubs that has sparked the Mets’ recent string of success. They are 16-10 since that win.

In the series opener against the Brewers last week, he reached base six times, going 4-for-4 with a double, triple, two walks, and a stolen base.

“If he started doing that every night, he’s playing on Tuesday,” Mets manager Terry Collins said, referring to the upcoming All-Star Game.

In Friday’s series opener against the Pirates, he slugged a solo home to tie the game at two.

Since his return, he has hit three home runs with 12 runs batted. He was 11-for-32 (.344) with a 1.042 on-base-plus-slugging percentage in 10 games in July entering Saturday, when he was hitting sixth and playing center fielder in the Mets’ lineup against the Pirates’ A.J. Burnett.

It is the type of potential Nieuwenhuis teased the Mets with last season as a rookie when he burst onto the season before his production plummeted and he was optioned to Triple-A Buffalo.

He then was sustained a partial tear of the plantar fiscia in his right foot to end his campaign in the minors.

“I’m just more relaxed at the plate and trying to stay as short as I can to the ball,” Nieuwenhuis said. “I’m mentally relaxed and putting the work in the cage and addressing that during the game. That’s about it.”